Conservation tillage increased soil bacterial diversity and improved soil nutrient status on the Loess Plateau in China

Abstract

ABSTRACT Conservation tillage can improve the soil nutrient status in drylands. This improvement is partially attributable to changes in the soil bacteria. In this study, we explored the bacterial factors involved in soil nutrients improvement under conservation tillage based on an 8-year in situ field trial. Two conservation tillage methods, no tillage (NT) and subsoiling tillage (ST) were used, and a moldboard plow (CT) was used as a control. The results indicated that compared to the CT, NT and ST significantly increased ACE indices by 12.4% and 10.5%, Shannon indices by 22.8% and 18.8%, respectively and this increase was positively correlated with the soil organic matter (SOM), available nitrogen (AN) and available phosphorus (AP) contents. In addition, Acidobacteria, Firmicutes and Nitrospirae were more abundant in the NT (20.8%, 5.2%, 7.04%) and ST (22.9%, 9.9%, 7.1%), while Planctomycetes was lower in the NT (−22.8%) and ST (−19.9%) compared to CT. Further analyses showed that the increase in the abundance of Acidobacteria was positively correlated with SOM, AP and AN. Overall, conservation tillage increased bacterial diversity and abundance and tested beneficial for soil nutrient improvement and the increased abundance of Acidobacteria might play an important role in soil nutrient improvement.